Hub for a communications network

ABSTRACT

A hub for a communications network, a base hub (10), multiple communications ports (64) on the base hub (10), a motherboard (13) on which is mounted circuitry (62) for operation in a communications network, an expansion port opening (101) in the base hub (10), an interconnection board (42) in the base hub (10) carrying circuitry for operation in a communications network, the interconnection board (42) pointing toward the expansion port opening (101) for electrical connection to an expansion module (20) containing additional communication ports (64), and containing a mating interconnection board (121) for connection to the interconnection board (42) in the base hub (10).

FIELD OF THE INVENTION

The invention relates to a hub for a communications network, and moreparticularly, to a hub that is capable of being upgraded with additionalcommunication ports.

BACKGROUND OF THE INVENTION

According to U.S. Pat. No. 4,858,070, a known interconnection mechanismis constructed with multiple communication ports on respectivemotherboards of duplicate construction. Post headers are on respectivemotherboards to connect the motherboards to one another in a stackedarrangement. The motherboards are duplicates of one another withoutactive circuitry on the motherboards. The active circuitry is embodiedin a cassette. The motherboards are contained in C-shaped enclosuresthat receive respective cassettes containing the active circuitry. Forexample, each cassette contains active circuitry for operating a diskdrive. Cassette connectors on respective motherboards connect thecommunication ports on the motherboards to respective cassettes.

The known interconnection mechanism, according to the patent, requiresactive circuitry in a cassette that serves solely one motherboard. Eachmotherboard has a fixed number of communication ports. When additionalcommunication ports are desired, the active circuitry must be duplicatedin an additional cassette to serve the additional communication ports onanother motherboard. Consequently, the communication ports on onemotherboard are unable to be connected to the same active circuitry thatserves a different motherboard. The known interconnection mechanismrequires the expense of additional active circuitry whenever the systemis upgraded or expanded with additional communication ports.

Various office equipment, such as multiple computers, peripheral devicesand automated factory machines, are located at various work sites in abuilding. A communications network comprises, apparatus in the form ofwiring and associated electronic apparatus that link together thevarious office equipment for the purpose of communicating with eachother by encoded electronic messages that are routed over the network.The electronic apparatus includes, electronic circuitry driven bynetwork software to provide an electronic identification for each itemof office equipment, and to encode and route the messages to the properequipment.

A known form of network apparatus comprises, a network hub with multiplecommunication ports grouped with the hub. The office equipment, locatedat various work sites near the hub, are linked to the hub by electricalcables that plug into the communication ports. The hub embodies networkcircuitry that electronically links each of the communication ports tothe network. The network can be expanded in size to reach officeequipment at distant work sites, for example, by using additional hubsthat are linked, one to another, by what is known as backbone wiring.Each of the additional hubs provides additional communications portsthat connect more office equipment into the network. A network with morethan one hub is needed to serve a large office, where the work sites aredistributed over large areas of a building or on different floors of abuilding. However, many smaller offices of different sizes exist in themarketplace, which can be served by only one hub. Even among thesesmaller offices the number of communication ports varies extensively.Providing a hub with different numbers of communication ports to servethe needs of different offices requires a complex inventory of differentparts, and a large number of hubs of different construction. A problemto be solved is to provide a network hub that is easily adaptable with asmall number of communication ports or with a larger number ofcommunication ports.

A small office can not afford an expensive a hub constructed with morecommunication ports than are needed. The marketplace has a need for anetwork hub of least expense, which has a limited number ofcommunications ports to link together a limited number of work sites inan office of small size. The marketplace further has a need for a hubthat is capable of an upgrade to add additional communications ports,thereby to serve an office that grows in size, needing morecommunications ports. A hub that is capable of an upgrade to addadditional communications ports advantageously adapts the hub to servedifferent offices of varied sizes. By providing the hub with thecapability for an upgrade, a network of original small size and leastexpense becomes expandable with a capacity for additional communicationsports, without the need for additional hubs.

SUMMARY OF THE INVENTION

According to the invention, a hub for a communications networkcomprises, a base hub that contains multiple communications ports linkedto circuitry for operation in a communications network, and the hub iscapable of an upgrade with additional communication ports, by providingan expansion port opening in the base hub, and an interconnection boardfacing the expansion port opening for connection to an expansion modulecontaining additional communication ports. The interconnection board isa feature that advantageously eliminates the need for wiring or cablesto interconnect the hub with the additional communication ports in anexpansion module.

According to an embodiment, the circuitry for operation in acommunications network is on a motherboard. A card edge connector on themotherboard faces an expansion port opening in the base hub. Aninterconnection board carrying a card edge connector and networkmanagement circuitry for operation in a communications network faces theexpansion port opening for connection to an expansion module containingadditional communication ports and a mating interconnection board forconnection to the card edge connector when the expansion module ismounted over the expansion port opening in the base hub.

According to an embodiment, the interconnection board is removable fromthe hub, and the interconnection board can add additional capability,such as, an upgrade to a more powerful MPU of the network electronics.

The interconnection board is removably connected to the motherboard forexchange with an upgrade interconnection board provided with upgradednetwork management circuitry.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a network hub for use in a communicationsnetwork and an expansion module, illustrated with parts separated fromone another;

FIG. 2 is an isometric view of a bottom side of the expansion modulethat is shown in FIG. 1;

FIG. 3 is an isometric view of the hub as shown in FIG. 1, with partsseparated from one another;

FIG. 4 is a side view of a portion of an interconnection mechanism,which portion is in the expansion module that is shown in FIG. 2;

FIG. 5 is a side view of an interconnection mechanism comprising, theportion as shown in FIG. 3 and another portion that is inside the hubshown in FIG. 1;

FIG. 6 is an isometric view of a bottom side of the hub that is shown inFIG. 1;

FIG. 7 is a view similar to FIG. 3, with parts cut;

FIG. 8 is an isometric view of an underside of a lid; and

FIG. 9 is a view similar to FIG. 1, with the expansion module stackedagainst the base hub and interlocked to resist movement parallel tothree orthogonal axes.

DETAILED DESCRIPTION

With reference to FIG. 1 a network apparatus comprises, an enclosure inthe form of a base hub 10 and an enclosure in the form of an expansionmodule 20.

As shown in FIG. 7, the base hub 10 encloses a motherboard 43 fabricatedas a circuit board, with conventional conducting paths on the circuitboard forming electrical circuitry 44 on the motherboard 43. Withreference to FIGS. 3 and 5, mounted on the motherboard 43 in the basehub 10 are electronic circuit components and the power supply comprisingactive circuitry 62, shown diagrammatically, including a power source,for operation in a communications network. For example, the network mayrequire the active circuitry 62 to be compatible with an Ethernet systemor, instead, with a Token Ring system. For either of the systems, thecircuit components comprising the active circuitry 62 are conventionaland known in the industry.

Also mounted on the motherboard 43 in the base hub 10 are multipleelectrical connectors known in the industry and comprising, multiplecommunication ports 64, FIGS. 3 and 6, facing an exterior of the basehub 10 for connection to cables extending from various office equipmentlocated at various work sites. The known use of the communication ports64 in a communications network will now be described. For example,various office equipment, located at various work sites near the basehub 10, have electrical cables that plug into respective communicationports 64 to link the office equipment to the base hub 10. The base hub10 embodies the known active circuitry 62 that electronically links eachof the communication ports 64 to the network. The circuitry 44 on themotherboard 43 in the base hub 10 connects the active circuitry 62 withthe communication ports 64. The active circuitry 62 on the motherboard43 in the base hub 10 links together the network circuitry and themultiple communication ports 64 to comprise a communications network forthe various office equipment that have electrical cables that plug intorespective communication ports 64. The various office equipment becomelinked to the network to communicate with one another over the network.

The base hub 10 provides a communications network of least expense and alimited number of communication ports 64 to link together a limitednumber of work sites in an office of small size. The hub 10 is capableof an upgrade, thereby to serve an office that grows in size, needingadditional communication ports 64. An interconnection mechanism 16, asshown in FIGS. 4 and 5, is provided for adding the additionalcommunication ports 64. For example, a portion of the interconnectionmechanism 16 is in the base hub 10. As shown in FIG. 1, the base hub 10is provided with an expansion port opening 101. Exposed at the openingis a portion of the interconnection mechanism 16 comprising, a circuitboard in the form of an interconnect board 42 and an electricalconnector 45 on the interconnect board 42. With reference to FIG. 3, theinterconnect board 42 is fabricated as a circuit board, withconventional conducting paths on the circuit board forming electricalcircuitry 41. For example, the connector 45 comprises a conventionalcard edge connector having electrical contacts that connect with thecircuitry 41, FIG. 7, on the interconnect board 42. The circuitry 41extends to an edge 142 on the interconnect board 42. The circuitry 41 atthe edge 142 removably plugs into an electrical connector 145 mounted onthe motherboard 43 in the base hub 10.

For example, the connector 145 comprises a conventional card edgeconnector having electrical contacts that frictionally engage thecircuitry 41 at the edge 142 on the interconnect board 42. Theelectrical contacts connect with the electrical circuitry 44, FIG. 7, onthe motherboard 43. Thus, the interconnect board 42 and the electricalconnector 145 are constructed for disconnect mating to interconnectelectrically the circuitry 41 on the interconnect board 42 and thecircuitry 44 on the motherboard 43 in the base hub 10.

For example, a portion of the interconnection mechanism 16 is in anexpansion module 20. With reference to FIG. 2, a bottom side of theexpansion module 20 is provided with a hub connection cavity 37 at whichprojects another portion of the interconnection mechanism 16 comprising,a mating interconnect board 121. The mating interconnect board 121 isexposed at the cavity 37 for disconnect mating with the connector 45 andthe interconnect board 42. The interconnect board 42 and the connector45 are exposed at the opening 101 for disconnect mating with the matinginterconnect board 121. When the expansion module 20 is stacked againstthe base hub 10, FIG. 9, the bottom side of the expansion module 20covers the expansion port opening 101. An edge 123 on the matinginterconnect board 121 removably inserts into the connector 45.

The mating interconnect board 121 is fabricated as a circuit board withconventional conducting paths that form electrical circuitry 124, FIG.2, on the mating interconnect board 121. The circuitry 124 extends tothe edge 123 on the mating interconnect board 121. The circuitry 124 atthe edge 123 of the mating interconnect board 121 becomes inserted intothe connector 45. Thus, the mating interconnect board 121 mates with theelectrical connector 45 to interconnect electrically the circuitry 124on the mating interconnect board 121 and the circuitry 41 on theinterconnect board 42.

With reference to FIG. 4, the interconnection mechanism 16 furthercomprises, a circuit board in the form of a second motherboard 43, andadditional communication ports 64 mounted on the second motherboard 43.The additional communication ports 64 are duplicates of thecommunication ports 64 described in conjunction with the motherboard 43in the base hub 10. The additional communication ports 64 are mounted inthe same positions with respect to the duplicate motherboard 43 that thecorresponding communication ports 64 are mounted with respect to themotherboard 43 in the base hub 10. The respective motherboards 43receive the corresponding communication ports 64 in the same places onthe respective motherboards. The additional communication ports face anexterior of the expansion module 20 for connection to cables extendingfrom various office equipment at various work sites.

An electrical connector, for example, a conventional post header 130, ismounted on the underside of the second motherboard 43. The conventionalpost header 130 mates with an electrical connector in the form of a postreceiving receptacle 122 mounted on the mating interconnect board 121.

For example, the post header 130 has conducting posts 131 that projectthrough the second motherboard 43. For example, the post receivingreceptacle 122 contains electrical contacts that frictionally engage theconducting posts 131 that project from the post header 130. Theelectrical contacts on the post receiving receptacle 122 engage theelectrical circuitry 124 on the mating interconnect board 121.

The second motherboard 43 is fabricated as a circuit board, withconventional conducting paths on the circuit board forming additions tothe electrical circuitry 44 on the motherboard 43. The additions to theelectrical circuitry 44 on the second motherboard 43 link the additionalcommunication ports 64 with respective posts 131 on the conventionalpost header 130. The circuitry 44 on both the motherboards 43 areduplicates of one another. Some of the circuitry 44 is unused, dependingupon which of the motherboards 43 is being constructed. For example, thecircuitry 44 for interconnecting the active circuitry 62 including thepower supply and other components of the network electronics on themotherboard 43 in the base hub 10 is present and unused on themotherboard 43 in the expansion module 20 that is constructed withoutthe selected components of active circuitry 62. Further, for example,the portions of the circuitry 44 for interconnecting the post header 130with the additional communication ports 64 is present and unused on themotherboard 43 in the base hub 10 on which the active circuitry 62 ispresent. Additional components of the network electronics may be on themotherboard 43 in the expansion module that are not present on themotherboard 43 in the base hub 10. Such additional components can beinterconnected by circuitry on the motherboard 43 that is unused on themotherboard 43 in the base hub 10.

With reference to FIGS. 4 and 5, disconnect mating of the secondmotherboard 43 with the motherboard 43 will now be described. Themotherboard 43 having the active circuitry 62 is provided with theconnector 145 and the interconnect board 42 and the connector 45. Thesecond motherboard 43 without the active circuitry 62 is provided withthe post header 130 and the receptacle 122 and the mating interconnectboard 121. When the mating interconnect board 121 is disconnectablymated with the connector 45, the additional communication ports 64 onthe second motherboard is added to a communications network being servedby the active circuitry 62.

A lid 23, FIG. 3, is constructed to removably cover the expansion portopening 101 in the base hub 10. The lid 23 is removable from the opening101 to permit interconnection of the portion of the interconnectionmechanism shown in FIG. 4, with the remainder of the interconnectionmechanism, as shown in FIG. 5. The lid 23 is replaceable over aduplicate opening 101 in the expansion module 20, FIG. 1. The duplicateopening 101 in the expansion module 20, when uncovered by removal of thelid 23, permits the addition of additional communication ports 64 bystacking another duplicate expansion module 20. For example, withreference to FIG. 4, a duplicate connector 145 is mounted on the secondmotherboard 43. Another interconnect board 42 having a correspondingconnector 45 thereon, is removably connected with the connector 145 onthe second motherboard 43. The duplicate connector 45 and theaccompanying interconnect board 42 are exposed at the duplicate opening101 for connection with a duplicate expansion module 20. Thus, theinterconnection mechanism 16 is adaptable with an additionalinterconnect board 42 and an additional connector 45, which adapts theexpansion module 20 for adding another expansion module 20, for example,by stacking a duplicate expansion module 20 against the expansion module20 that is shown in FIGS. 1 and 2.

Each interconnect board 42 at least in the base hub 10 is removable froma corresponding connector 145 to be replaced by an upgrade interconnectboard 42 having thereon upgrade circuitry, for example upgrade networkmanagement circuitry. The circuitry is known in the industry but hasbeen relocated to appear on the interconnect boards 42. The networkmanagement circuitry comprises circuit components having the electricalvalues identified in tables that are appended herein. According to thetables, a number of different upgrade interconnect boards 42 can vary inconstruction according to the selection of components organizedaccording to the tables.

As shown in FIG. 3, the enclosure of the base hub 10 is bipartite, andcomprises, a hollow base 12 and a hollow cover 14 that are assembledtogether to enclose the interconnection mechanism. For example, the base12 and cover 14 are molded of plastics material that is conductive onthe inside surfaces for electrical grounding and RF and EMI shielding.The plastics material itself may be conductive, or rendered conductiveby being plated with a conducting coating of metal on interior surfaces.Similarly, the enclosure of the expansion module 20 is bipartite, andcomprises, a molded, hollow base 120 and a molded, hollow cover 140 thatare conductive on interior surfaces, and that are assembled together toenclose the portion of the interconnection mechanism as shown in FIGS. 2and 4. Air vents 67 are provided by small apertures through the base hub10 and the expansion module 20.

Additional RF and EMI shielding is provided at each correspondingopening 101, in the corresponding base hub 10 and in the expansionmodule 20, by conducting resilient spring clips 106 and 107 distributedaround a periphery of the respective openings 101. The clips 106 and 107are fabricated of BeCu, for example, and engage the conductive coatingson the corresponding interiors of the respective base hub 10 and theexpansion module 20. With reference to FIG. 8, the lid 23 is provided onits underside with projecting flanges 236 that compressively engagecorresponding clips 107 when the lid 23 covers a corresponding opening101. The lid is provided further on its underside with projectingflanges 237 that compressively engage corresponding clips 106 when thelid 23 covers a corresponding opening 101. A stepped outer edge 231 onthe underside of the lid 23 registers in the edge of the correspondingopening 101. Fasteners 232 are captive on the lid 23 and removablysecure in corresponding sockets 233 adjacent to the correspondingopening 101. The lid 23 is molded, for example, of unitary plasticsmaterial coated on its underside with a conducting coating 230 of metal.The flanges 236 and 237, being coated with the coating 230, establishelectrical contact with the clips 106 and 107 to extend electricalshielding continuously through the clips 106 and 107 and the lid 23 thatcovers the corresponding opening 101. With reference to FIG. 2, thecavity 37 is encircled by a rectangular shroud 95, that projects toreceive the connector 45 on a corresponding interconnect board 42, whenthe mating interconnect board 122 mates with the corresponding connector45. A raised bridging plate 96 projects forwardly of the shroud 95.Additional conductive plating 230 is on the shroud 95 and the bridgingplate 96. When the expansion module 20 covers a corresponding opening101, the shroud 95 will compressively engage the clips 107, and thebridging plate 96 will bridge across the corresponding opening 101 andcompressively engage some of the clips 106. Thereby, RF and EMIshielding bridges across the corresponding opening 101 when thecorresponding opening 101 is covered by an expansion module 20.

As shown in FIGS. 2 and 3, fasteners 87 project through openings 77through the bases 12 and 120 of the respective base hub 10 and expansionmodule 20. The fasteners 87 project through openings 99 in respectivemotherboards 43. The openings 99 are aligned along respective axes 98.Unitary, columnar support members 97 are aligned along the axes 98 anddepend from the covers 14 and 140, respectively, of the base hub 10 andthe expansion module 20. The support members 97 are hollow to receiverespective fasteners 87 that are anchored in the support members 97 toretain together the bipartite parts, respectively, of the base hub 10and the expansion module 20. The support members 97 are coated with aconductive material to provide ground connections for engagement withground portions of the circuitry 44 on the corresponding motherboard 43near the openings 99 through the motherboard 43. Similarly, as shown inFIGS. 2 and 3, unitary and hollow projecting alignment posts 88 projectinside the respective bases 12 and 120 on the base hub 10 and theexpansion module 20. The alignment posts 88 are in alignment withunitary and hollow columns 47 that project inside beside opposite endsof each of the openings 101 in the covers 14 and 140 of the respectivebase hub 10 and expansion module 20. The hollow alignment columns 47provide open sockets that fit over the posts 88. The hollow alignmentposts 88 receive fasteners 89 that pass through the alignment posts 88and become anchored in the columns 47. The alignment posts 88 and thecolumns 47 are coated with conductive material to provide groundconnections for engagement with ground sections of the circuitry 44 onthe motherboard 43 adjacent to alignment apertures 430 through themotherboard 43.

With reference to FIGS. 3 and 7, the alignment posts 88 are in alignmentwith respective alignment apertures 430 through respective motherboards43. The apertures 430 are located adjacent opposite ends of respectiveconnectors 145 on the motherboards 43. The motherboards 43 are assembledto respective base hub 10 and expansion module 20 by registration of theapertures 430 over the alignment posts 88. With respect to the expansionmodule 20, registration of the aperatures 430, through the correspondingmotherboard 43, with the alignment columns 47 in the expansion module20, will prealign the posts 131 with the post receiving receptacle 122for blind mating of the posts with the receptacle 122. The matinginterconnect board 121 already will have been attached by fasteners tothe base 12 of the expansion module 20. The fasteners 89 project throughthe apertures 430 to anchor in the alignment columns 47. The fasteners89 and 87 are self threading screws, for example. As shown in FIG. 3,respective apertures 430, respective alignment posts 88 and respectivefasteners 89 extend along respective axes 261.

With reference to FIGS. 3 and 7, unitary with respective columns 47,channel shaped card guides 48 are beside respective openings 101 in thebase hub 10 and the expansion module 20. The card guides 48 extendlengthwise along the respective columns 47, from the respectiveopenings, and toward the respective connectors 145 on respectivemotherboards 43. The respective connectors 145 face toward respectiveopenings 101. The card guides 48 extend from the openings 101 to theconnector 145.

With reference to FIGS. 1, 3 and 7, blind mate connection of respectiveinterconnect boards 42 will now be described. Respective interconnectboards 42 are inserted into respective openings 101, by insertingopposite edges of the interconnect boards 42 into and along open ends ofthe card guides 48, FIG. 3. The card guides 48 are aligned withrespective connectors 145 on the motherboards 43. The card guides 48align and guide the respective interconnect boards 42 without theconnectors 145 being visible, thereby providing prealignment of theinterconnect boards 42 for blind mating with the connectors 145. FIGS. 3and 7 show the interconnect board 42 being prealigned by the card guides48, and partially inserted along the channel shaped card guides 48. FIG.1 shows the interconnect board 42 fully inserted into the base hub 10and mating with the corresponding connector 145, as shown further inFIG. 5.

Additional features of the base hub 10 and the expansion module 20 willnow be described. With reference to FIGS. 4 and 5, multiple visualstatus indicators 50 in the form of LEDs, for example, are mounted onthe motherboard 43 and circuitry 44 in the base hub 10, and on themating interconnect board 121 and the circuitry 124, for indicating theoperating status of the communication ports 64 and other hub functions.As known in the industry, the LEDs illuminate to indicate, for example,whether the communication ports 64 are receiving or transmitting. TheLEDs are visible at the exteriors of the base hub 10 and the expansionmodule 20, respectively.

As shown in FIG. 6, the base hub 10 comprises, external connections to apower source, for example, an AC, three prong, input port 622 and a DCinput port 621, both facing an exterior of the base hub 10 for supplyingelectrical power to the motherboard 43 in the base hub 10. The base hub10 further comprises, a serial port 66 and a network backbone connectionport 63, both facing an exterior of the base hub, for example, a ringin/out connection, or, alternatively, not shown, an AUI port, optionallyfor linking the base hub 10 to a larger area network. The circuitry 44on the motherboard 43 connects the ports 621, 622, 66 and 63 to theactive circuitry 62 that also includes a fan in a known manner.

With reference to FIGS. 1, 2 and 3, each of the base hub 10 and theexpansion module 20 is constructed for prealignment and blind mating ofa corresponding connector 45 with a mating interconnect board 121. Thecorresponding opening 101 on either the base hub 10 or the expansionmodule 20 extends through a raised mesa 31 with sloped sides. Thecorresponding connector 45 and the corresponding mating interconnectboard 121 mate along an axis of mating that extends through the opening101 and through one of the sides of the mesa 31. A raised step 33circumscribes three sides of the mesa 31. The step 33 is behind a frontsurface 35. Channel shaped tracks 36 extend parallel to the axis ofmating and along two sides of the raised step 33. The channel shapedtracks 36 have open front ends. The mesa 31 is between the tracks 36.

With reference to FIG. 2, unitary fingers 137 project along theunderside of the expansion module 20. The fingers 137 are in anarrangement of two series that extend toward one another to definetracks on the expansion module. A mesa receiving cavity 39 is recessedin the underside between the two series of fingers 137. The mesareceiving cavity 39 has sloping sides and an open side facing toward arear of the expansion module 20. Each of the tracks defined by theseries of fingers 137 extends parallel to the axis of mating for whenthe mating interconnect board 121 mates with the corresponding connector45. The corresponding connector 45 can be at an opening 101 in eitherthe base hub 10 or another expansion module 20. Both series of fingers137 are stepped back from a rear of the expansion module 20, to rest theexpansion module upon the base hub prior to prealignment.

Prealignment and blind mating is accomplished according the followingprocedure. The underside of the expansion module 20, as shown in FIG. 1,rests against a corresponding front surface 35 on the base hub 10, or,alternatively, a corresponding front surface 35 on another expansionmodule 20. The expansion module is moved parallel to an Y-axis, causingthe tracks defined by the series of fingers 137 to enter and slide alongrespective tracks 36. With the tracks defined by the series of fingers137 in respective tracks 36, the expansion module 20 is restrained frommovement parallel to the X-axis and parallel to the orthogonal Z-axis.The expansion module 20 in the tracks 36 prealigns the matinginterconnect board 121 and the corresponding connector 45 along the axisof mating. When the expansion module 20 is moved to cover the opening101, the mating interconnect board 121 and the corresponding connector45 are prealigned and blind mated, meaning, that they are aligned alongtheir axis of mating and are mated together without being in view.

With reference to FIG. 2, hook shaped latches 38 are resilientlypivotable on strap like hinges unitary with the expansion module 20. Atip on each of the latches 38 is aligned with a corresponding series offingers 137. With reference to FIG. 1, the tips of the latches 38 willenter corresponding latch receiving cavities 360 in respective tracks 36to lock the latches 38 in the tracks 36. The expansion module 20 thenbecomes interlocked from movement parallel to the three orthogonal axes,the X-Axis, the Y-Axis and the Z-axis. The latches 38 have handles thatare manually deflected by pulling on them to pivot the latches 38 andunhook them from the cavities 360. Continued pulling on the handles ofthe latches 38 occurs in the same direction as pulling on the expansionmodule 20 to cause removal of the expansion module slidably along thetracks 36.

An advantage of the invention resides in an interconnection mechanismfor adding additional communication ports to a network hub, so that thehub can serve an increased number of communication ports.

Other embodiments and modifications of the embodiment described areintended to be covered by the spirit and scope of the appended claims.

    __________________________________________________________________________                                   Token Ring Standard Management                                           Quantity                                                                           Reference                                      Item                                                                             Description     Part Number                                                                          -001 Designation                                    __________________________________________________________________________    1  Printed Circuit Board, MPM                                                                    1-026004-001                                                                         1                                                   2  Support Bracket, Vert. Interconnect                                                           058001-001                                                                           1                                                   3  Rivit           0-055054-002                                                                         2                                                   4  Socket, 32pin PLCC                                                                            63068-003                                                                            2                                                   5  Connector, 72 pin SIMM                                                                        7-382487-2                                                                           0                                                   6  Shorting Strap  63012-102                                                                            1                                                   7  Capacitor, Tantalum, 4.7 μF, 3528                                                          40062-010                                                                            1    C1                                             8  Capacitor, 47 pF, 0603                                                                        40061-048                                                                            1    C2                                             9  Capacitor, 0.1 μF, 25 V (0603)                                                             40061-042                                                                            54   C3-C52,C60-C63                                 10 Header, 2 × 1                                                                           63011-002                                                                            1    J2                                             11 Connector, 2 × 15 Edge                                                                  0-063131-002                                                                         1    J3                                             12 Resistor, 33,0603                                                                             40122-330                                                                            1    R1,R4                                          13 Resistor, 10k,0603                                                                            40122-103                                                                            23   R2-R3,R5-R22,R24-R25,R44                       14 Resistor, 1k,0603                                                                             40122-102                                                                            5    R26-R30                                        15 Resistor, 4.7k,0603                                                                           40122-472                                                                            5    R31-R14,R46                                    16 Resistor, 110,0603                                                                            40122-111                                                                            19   R36-R43,R47,R49,R54-R62                        17 Resistor, 0,0603                                                                              40122-000                                                                            2    R5,R45,R48                                     18 Processor, 60960JA                                                                            45149-002                                                                            1    U1                                             19 Processor, 80960JD                                                                            45149-003                                                                            0                                                   20 Programmed Logic                                                                              1-048C02-005                                                                         1    U2                                             21 Programmed Logic                                                                              1-048C02-006                                                                         1    U3                                             22 DRAM, 256kx16   45099-006                                                                            2    U5,U20                                         23 Programmed PROM (TRSA)                                                                        1-048C02-008                                                                         1    U6                                             24 Programmed PROM (TRA)                                                                         1-048C02-010                                                                         0                                                   25 Programmed PROM (ENSA)                                                                        1-048002-011                                                                         0                                                   26 Programmed PROM (ENA)                                                                         1-048002-013                                                                         0                                                   27 Oscillator, 32 MHz                                                                            45116419                                                                             1    U9                                             28 Dual 4 to 1 Mux/Demux                                                                         0-45208-001                                                                          0                                                   29 Octal Bus Transceiver, soic wb                                                                45085-245                                                                            4    U12-U15                                        30 Programmed Logic                                                                              1-048002-003                                                                         1    U16                                            31 Programmed Logic                                                                              1-048002-004                                                                         1    U17                                            32 Token Ring MAC  0-045211                                                                             1    U18                                            33 Token Ring Accelator                                                                          0-045210                                                                             0                                                   34 Programmed Logic                                                                              1-048002-007                                                                         1    U21                                            35 Programmed PROM (TRSB)                                                                        1-048002-009                                                                         t    U22                                            36 Programmed PROM (ENSB)                                                                        1-048002-012                                                                         0                                                   37 Quad 2 to 1 Mux, soic nb                                                                      45085-157                                                                            1    U23                                            38 Ferrite Bead, SMT                                                                             40110-001                                                                            2    Z1-Z2                                          39 Label, MAC Address                                                                            1-053022-001                                                                         1                                                   40 Label, MAC Address                                                                            1-053022-002                                                                         0                                                   41 Label, Serial Number                                                                          51043-004                                                                            1                                                   __________________________________________________________________________                                   Token Ring Advanced Management                                           Quantity                                                                           Reference                                      Item                                                                             Description     Part Number                                                                          -002 Designation                                    __________________________________________________________________________    1  Printed Circuit Board, MPM                                                                    1-026004-001                                                                         1                                                   2  Support Bracket Vert. Interconnect                                                            058001-001                                                                           1                                                   3  Rivit           0-055054-002                                                                         2                                                   4  Socket, 32pin PLCC                                                                            63068-003                                                                            2                                                   5  Connector, 72 pin SIMM                                                                        7-382487-2                                                                           1                                                   6  Shorting Strap  63012-102                                                                            11                                                  7  Capacitor, Tantalum, 4.7 μF, 3528                                                          40062-010                                                                            1    C1                                             8  Capacitor, 47 pF, 0603                                                                        40061-048                                                                            1    C2                                             9  Capacitor, 0.1 μF, 25 V (0603)                                                             40061-042                                                                            54   C3-C52,C60-C63                                 10 Header, 2 × 1                                                                           63011-002                                                                            1    J2                                             11 Connector, 2 × 15 Edge                                                                  0-063131-002                                                                         1    J3                                             12 Resistor, 33,0603                                                                             40122-330                                                                            2    R1,R4                                          13 Resistor, 10k,0603                                                                            40122-103                                                                            23   R2-R3,R5-R22,R24-R25,R44                       14 Resistor, 1k,0603                                                                             40122-102                                                                            5    R26-R30                                        15 Resistor, 4.7k,0603                                                                           40122-472                                                                            5    R31-R34,R46                                    16 Resistor, 110,0603                                                                            40122-111                                                                            19   R36-R43,R47,R49,R54-R62                        17 Resistor, 0,0603                                                                              40122-000                                                                            1    R45,R48                                        18 Processor, 60960JA                                                                            45149-002                                                                            0                                                   19 Processor, 80960JD                                                                            45149-003                                                                            1    U1                                             20 Programmed Logic                                                                              1-048C02-005                                                                         1    U2                                             21 Programmed Logic                                                                              1-048C02-006                                                                         1    U3                                             22 DRAM, 256kx16   45099-006                                                                            3    U4-U5,U20                                      23 Programmed PROM (TRSA)                                                                        1-048C02-008                                                                         0                                                   24 Programmed PROM (TRA)                                                                         1-048C02-010                                                                         1    U6                                             25 Programmed PROM (ENSA)                                                                        1-048002-011                                                                         0                                                   26 Programmed PROM (ENA)                                                                         1-048002-013                                                                         0                                                   27 Oscillator, 32 MHz                                                                            45116-419                                                                            1    U9                                             28 Dual 4 to 1 Mux/Demux                                                                         045208-001                                                                           0                                                   29 Octal Bus Transceiver, soic wb                                                                45085-245                                                                            4    U12-U15                                        30 Programmed Logic                                                                              1-048002-003                                                                         1    U16                                            31 Programmed Logic                                                                              1-048002-004                                                                         1    U17                                            32 Token Ring MAC  0-045211                                                                             1    U18                                            33 Token Ring Accelator                                                                          0-045210                                                                             1    U19                                            34 Programmed Logic                                                                              1-048002-007                                                                         1    U21                                            35 Programmed PROM (TRSB)                                                                        1-048002-009                                                                         0                                                   36 Programmed PROM (ENSB)                                                                        1-048002-012                                                                         0                                                   37 Quad 2 to 1 Mux,soic nb                                                                       45085-157                                                                            1    U23                                            38 Ferrite Bead,SMT                                                                              401l0-001                                                                            2    Z1-Z2                                          39 Label, MAC Address                                                                            1-053022-001                                                                         1                                                   40 Label, MAC Address                                                                            1-053022-002                                                                         0                                                   41 Label, Serial Number                                                                          51043-004                                                                            1                                                   __________________________________________________________________________                                   Ethernet Standard Management                                             Quantity                                                                           Reference                                      Item                                                                             Description     Part Number                                                                          -003 Designation                                    __________________________________________________________________________    1  Printed Circuit Board, MPM                                                                    1-026004-001                                                                         1                                                   2  Support Bracket, Vert. Interconnect                                                           058001-001                                                                           1                                                   3  Rivit           0-055054-002                                                                         2                                                   4  Socket, 32pin PLCC                                                                            63068-003                                                                            2                                                   5  Connector, 72 pin SIMM                                                                        7-382487-2                                                                           0                                                   6  Shorting Strap  63012-102                                                                            1                                                   7  Capacitor, Tantalum, 4.7 μF, 3528                                                          40062-010                                                                            1    C1                                             8  Capacitor, 47pF, 0603                                                                         40061-048                                                                            0                                                   9  Capacitor, 0.1 μF, 25 V (0603)                                                             40061-042                                                                            32   C3-C6,C8-C31,C51-C52,C60-C61                   10 Header, 2 × 1                                                                           63011-002                                                                            1    J2                                             11 Connector, 2 × 15 Edge                                                                  0-063131-002                                                                         1    J3                                             12 Resistor, 33,0603                                                                             40122-330                                                                            2    R1,R4                                          13 Resistor, 10k,0603                                                                            40122-103                                                                            21   R2-R3,R5-R22,R44                               14 Resistor, 1k,0603                                                                             40122-102                                                                            0                                                   15 Resistor, 4.7k,0603                                                                           40122-472                                                                            0                                                   16 Resistor, 110,0603                                                                            40122-111                                                                            19   R36-R43,R47,R49,R54-R62                        17 Resistor, 0,0603                                                                              40122-000                                                                            1    R5                                             18 Processor, 60960JA                                                                            45149-002                                                                            1    U1                                             19 Processor, 809603D                                                                            45149-003                                                                            0                                                   20 Programmed Logic                                                                              1-048C02-005                                                                         1    U2                                             21 Programmed Logic                                                                              1-048C02-006                                                                         1    U3                                             22 DRAM, 256kx16   45099-006                                                                            1    U5                                             23 Programmed PROM (TRSA)                                                                        1-048C02-008                                                                         0                                                   24 Programmed PROM (TRA)                                                                         1-048C02-010                                                                         0                                                   25 Programmed PROM (ENSA)                                                                        1-048002-011                                                                         1    U6                                             26 Programmed PROM (ENA)                                                                         1-048002-013                                                                         0                                                   27 Oscillator, 32MHz                                                                             45116-419                                                                            1    U9                                             28 Dual 4 to 1 Mux/Demux                                                                         0-45208-001                                                                          1    U11                                            29 Octal Bus Transceiver, soic wb                                                                45085-245                                                                            0                                                   30 Programmed Logic                                                                              1-048002-003                                                                         0                                                   31 Programmed Logic                                                                              1-048002-004                                                                         0                                                   32 Token Ring MAC  0-045211                                                                             0                                                   33 Token Ring Accelator                                                                          0-045210                                                                             0                                                   34 Programmed Logic                                                                              1-048002-007                                                                         1    U21                                            35 Programmed PROM (TRSB)                                                                        1-048002-009                                                                         0                                                   36 Programmed PROM (ENSB)                                                                        1-048002-012                                                                         1    U22                                            37 Quad 2 to 1 Mux, soic nb                                                                      45085-157                                                                            0                                                   38 Ferrite Bead, SMT                                                                             40110-001                                                                            2    Z1-Z2                                          39 Label, MAC Address                                                                            1-053022-001                                                                         0                                                   40 Label, MAC Address                                                                            1-053022-002                                                                         1                                                   41 Label, Serial Number                                                                          51043-004                                                                            1                                                   __________________________________________________________________________                                   Ethernet Advanced Management                                             Quantity                                                                           Reference                                      Item                                                                             Description     Part Number                                                                          -004 Designation                                    __________________________________________________________________________    1  Printed Circuit Board, MPM                                                                    1-026004-001                                                                         1                                                   2  Support Bracket, Vert. Interconnect                                                           058001-001                                                                           1                                                   3  Rivit           0-055054-002                                                                         2                                                   4  Socket, 32pin PLCC                                                                            63068-003                                                                            2                                                   5  Connector, 72 pin SIMM                                                                        7-382487-2                                                                           1                                                   6  Shorting Strap  63012-002                                                                            1                                                   7  Capacitor, Tantalum, 4.7 μF, 3528                                                          40062-010                                                                            1    Cl                                             8  Capacitor, 47pF, 0603                                                                         40061-048                                                                            1                                                   9  Capacitor, 0.1 μF, 25 V (0603)                                                             40061-042                                                                            32   C3-C6,C8-C31,C51-C52,C60-C61                   10 Header, 2 × 1                                                                           63011-002                                                                            1    J2                                             11 Connector, 2 × 15 Edge                                                                  0-063131-002                                                                         1    J3                                             12 Resistor, 33,0603                                                                             40122-330                                                                            2    R1,R4                                          13 Resistor, 10k,0603                                                                            40122-103                                                                            21   R2-R3,R5-R22,R44                               14 Resistor, 1k,0603                                                                             40122-102                                                                            0                                                   15 Resistor, 4.7k,0603                                                                           40122-472                                                                            0                                                   16 Resistor, 110,0603                                                                            40122-111                                                                            19   R36-R43,R47,R49,R54-R62                        17 Resistor, 0,0603                                                                              40122-000                                                                            0                                                   18 Processor, 60960JA                                                                            45149-002                                                                            0                                                   19 Processor, 80960JD                                                                            45149-003                                                                            1    U1                                             20 Programmed Logic                                                                              1-048C02-005                                                                         1    U2                                             21 Programmed Logic                                                                              1-048C02-006                                                                         1    U3                                             22 DRAM, 256kx16   45099-006                                                                            2    U4-U5                                          23 Programmed PROM (TRSA)                                                                        1-048C02-008                                                                         0                                                   24 Programmed PROM (TRA)                                                                         1-048C02-010                                                                         0                                                   25 Programmed PROM (ENSA)                                                                        1-048002-011                                                                         0                                                   26 Programmed PROM (ENA)                                                                         1-048002-013                                                                         1    U6                                             27 Oscillator, 32 MHz                                                                            45116-419                                                                            1    U9                                             28 Dual 4 to 1 Mux/Demux                                                                         0-45208-001                                                                          1    U11                                            29 Octal Bus Transceiver, soic wb                                                                45085-245                                                                            0                                                   30 Programmed Logic                                                                              1-048002-003                                                                         0                                                   31 Programmed Logic                                                                              1-048002-004                                                                         0                                                   32 Token Ring MAC  0-045211                                                                             0                                                   33 Token Ring Accelator                                                                          0-045210                                                                             0                                                   34 Programmed Logic                                                                              1-048002-007                                                                         1    U21                                            35 Programmed PROM (TRSB)                                                                        1-048002-009                                                                         0                                                   36 Programmed PROM (ENSB)                                                                        1-048002-012                                                                         0                                                   37 Quad 2 to 1 Mux,soic nb                                                                       45085-157                                                                            0                                                   38 Ferrite Bead, SMT                                                                             40110-001                                                                            2    Z1-Z2                                          39 Label, MAC Address                                                                            1-053022-001                                                                         0                                                   40 Label, MAC Address                                                                            1-053022-002                                                                         1                                                   41 Label, Serial Number                                                                          51043-004                                                                            1                                                   __________________________________________________________________________

What is claimed is:
 1. A hub for a communications network comprising:abase hub containing a motherboard, multiple communication ports andoperating circuitry of a communications network on the motherboard, thecommunications ports facing an exterior of the base hub for connectionto cables leading to work station sites, the base hub being adapted fora blind mating connection to the operating circuitry by being providedwith, an expansion port opening through the exterior of the base hub, acard edge connector facing toward said opening, and interconnectionboard receiving card guides, the card edge connector being connected tothe operating circuitry, and the card guides extending from said openingto the card edge connector to guide an interconnection board duringblind mating connection of the interconnection board with the card edgeconnector and the operating circuitry wherein the card guides extendalong a first axis of blind mating, and further comprising, guide trackson the exterior of the hub, the guide tracks extending toward theexpansion port opening along a second axis.
 2. A hub as recited in claim1, and further comprising: a removable lid covering the expansion portopening.
 3. A hub as recited in claim 1, and further comprising:conductive clips distributed along the expansion port opening, aremovable lid covering the expansion port opening, and conductiveshielding on the lid removably connected with the clips.
 4. A hub asrecited in claim 1, and further comprising:alignment posts in the basehub, the motherboard being received on the alignment posts, the cardguides extending along projecting columns on the base hub, and thecolumns being received on the alignment posts.
 5. A hub as recited inclaim 1, and further comprising: an upgrade interconnection boardprovided with upgrade network management circuitry, the upgrade boardbeing interchangeable with the interconnection board, and theinterconnection board being removably connected to the card edgeconnector for interchange with said upgrade interconnection board.
 6. Ahub as recited in claim 1, and further comprising: a network backboneconnector on the motherboard facing the exterior of the base hub forconnection to a network.
 7. A hub for a communications networkcomprising:a base hub containing a motherboard, multiple communicationports and operating circuitry of a communications network on themotherboard, the communications ports facing an exterior of the base hubfor connection to cables leading to work station sites, the base hubbeing adapted for a blind mating connection to the operating circuitryby being provided with, an expansion port opening through the exteriorof the base hub, a lid removably covering said opening, a card edgeconnector facing toward said opening, and card guides, the card edgeconnector being connected to the operating circuitry, and the cardguides extending from said opening to the card edge connector to guidean interconnection board during blind mating connection of theinterconnection board with the card edge connector and the operatingcircuitry wherein the card guides extend along a first axis of blindmating, and the exterior of the base hub has guide tracks extendingtoward the expansion port opening along a second axis.
 8. A hub asrecited in claim 7, and further comprising: conductive clips distributedalong the expansion port opening, and conductive shielding on the lidremovably connected with the clips.
 9. A hub as recited in claim 1, andfurther comprising: a network backbone connector on the motherboardfacing the exterior of the base hub for connection to a network.
 10. Ahub for a communications network comprising:a base hub containing amotherboard, multiple communication ports and operating circuitry of acommunications network on the motherboard, the communications portsfacing an exterior of the base hub for connection to cables leading towork station sites, the base hub being adapted for a blind matingconnection to the operating circuitry by being provided with, anexpansion port opening through the exterior of the base hub, a card edgeconnector facing toward said opening, and interconnection boardreceiving card guides, the card edge connector being connected to theoperating circuitry, and an interconnection board removably extendingalong the card guides and removably connected to the card edgeconnector, the card guides extending from said opening to the card edgeconnector to guide the interconnection board during blind matingconnection of the interconnection board with the card edge connector andthe operating circuitry wherein the card guides extend along a firstaxis of blind mating, and further comprising, guide tracks on theexterior of the hub, the guide tracks extending toward the expansionport opening along a second axis.
 11. A hub as recited in claim 10, andfurther comprising: electrical circuitry on the interconnection board, acard edge connector on the interconnection board connected with theelectrical circuitry and being exposed at the expansion port opening,and said card guides aligned along a direction of mating with said cardedge connector on the interconnection board.
 12. A hub as recited inclaim 10, and further comprising: an upgrade interconnection boardprovided with upgrade network management circuitry, the upgrade boardbeing interchangeable with the interconnection board, and theinterconnection board being removable from the card edge connector forinterchange with said upgrade interconnection board.
 13. A hub asrecited in claim 10, and further comprising: a network backboneconnector on the motherboard facing the exterior of the base hub forconnection to a network.